This disclosure is directed to a palletized cooling system as set forth. In particular, it is a cooling system which requires no power when shipped on board a train, on a flat car, on a flat bed trailer of a truck, or on ship board. All that is required for the operation of this equipment is ventilation so that fresh air can circulate. The air circulation is provided so that continued cooling is accomplished through the operation of a refrigeration system. This cooling method is effective to chill and maintain the static temperature for cold goods. It involves a multiple unit set of replicated storage boxes. One box, preferably having a common profile with all of the others, incorporates a power plant with cooling system.
The cooling system is connected to the cargo boxes with an external hose. The hose extends from the cooling box (that term will be applied to the power plant) and comprises branching conduits which connect to the cargo boxes. Each cargo box is preferably identical to all of the others. All of the boxes have a common foot print&lt;. The footprint can be either square or rectangular. If square, the sides are preferably four feet in length. These dimensions are conformed with the foot print of a "standard" pallet. The bottom panel of each box is preferably provided with at least at least one leg or "foot" at thereby elevating the bottom above a surface upon which the box rests for ease of lifting. The bottom panel is optionally provided with fifth and sixth legs thereby enabling tines of a forklift to be controllably inserted under the box for lifting. All of the boxes are provided with common dimensions on the bottom so that they can be either be stacked vertically or arranged horizontally. When empty, the boxes can be collapsed by folding sides thereby reducing the height of each box and significantly reducing storage space required to store empty boxes.
The cargo boxes are externally connected with a hose network which is rather simple to install and remove. The hose network can be extended in length. By adding different increments, the number of cargo boxes connected to the system can be increased to any suitable number N, where N is a whole number positive integer. In terms of cooling capacity, N is practically limited depending on the heat loss encountered in transit. In turn, that typically depends on the ambient temperature in the trailer or cargo hold of the vessel, and that in turn is dependent on the temperature differential maintained in the cargo box. The system operates at temperatures below freezing, if desired. Again, that depends on the amount of energy required to drop the temperature. It preferably operates with a flowing coolant which is chilled to some desired temperature level. For instance, many products can be shipped where it is maintained at about 35.degree. to 40.degree. F. The system, however, will also operate by circulating a coolant which is chilled below freezing so that items which are prefrozen in water (fish is one example) are maintained at that cold temperature. In general terms, the cooling system of the present disclosure maintains the frozen cargo at a desired temperature somewhere in the range of about 15.degree. F. at the low end to about 40.degree. F. at the high end. This range is merely representative, however, and the range can be extended further by the choice of different cooling liquids which are circulated in the system.
In the present disclosure, the cargo boxes are constructed so that they have a removable lid. The lid is positioned parallel to the base, as that term will be applied to the bottom side portion. The base has at least four legs on it, and preferably six legs. The six legs are deployed to define spaces between the legs. These spaces enable the insertion of the tines of a forklift to raise and lower the cargo box. The base is constructed as a bottom platform having fixed base dimensions. The fixed dimensions conform with the desired industry standard footprint which enables the devices to be loaded on a forklift and to be supported in the form of a pallet. In this instance, a disposable pallet is avoided and can be omitted because the base is itself pallet conformed. The base supports four walls which are upstanding walls defining the cargo box. The four walls are comprised of two long walls and two short walls, or alternately four walls of the same length. The four walls all hinge and fold to assemble in a shortened or compact structure. When folded, the four walls stack in a fashion enabling the box to be reduced in height so that the empty box, in a return trip, is easier to return. In effect, the return trip of the empty box is accomplished without shipping the box fully assembled. The sides fold down to thereby shorten the height. Approximately, the entire unit is shortened by about 60% to 70%, depending on specific dimensions of the box. The return trip, therefore enables approximately four, five, or six units to be stacked vertically in a location where only two units could have been stacked vertically while fully erect.
This box type construction with folding sides enables the cargo to be delivered and removed from the boxes. Then on the return trip, the boxes are simply stacked.
Each box is provided with its own lid. The lid is constructed with a surrounding lip, an adjacent internal seal ring, and an internally supported heat exchanger. The heat exchanger is in the lid. It is placed high up in the lid so that it is protected by the surrounding lid lip. It is mounted on the inside of the lid by suitable spaced hangers. The heat exchanger has the form of a repetitive coil of flat shape. It terminates at a pair of fittings which extend through the lid. This enables inlet and outlet connections to be accomplished. The connections are preferably side by side so that the inlet and outlet connections on a string of these cargo boxes are easily accomplished with a common pair of fluid flow lines. One is the delivery line, and the other is the return line. They are preferably provided with suitable fittings to assure that there is no confusion in connection.
The cooling system of the present disclosure is especially effective for shipping chilled or frozen items where the transport requires several days. It cooperates with a self contained cooling system. It is provided with a control which is adjusted so that the coolant circulated by the system is capable of sustaining a fixed temperature throughout the trip, voyage, or storage interval. To this end, the system utilizes a commonly connected external hose, really a pair of hoses, which are assembled in repetitive fashion for connection to the source of the chilled refrigerant.